Golang Batch Post Via Mux - json

Question

Hello I'm new to Golang and I'm attempting to do a batch POST with Mux. I want to be able to POST multiple "produce" items instead of just a single one.
Here I'm defining what a produce item is
// Define the produce structure
type Produce struct {
Name string `json:"name"`
Code string `json:"code"`
Unit_Price float64 `json:"unit_price"`
}
// Init produce var as a Produce slice
var produce []Produce
Here is my current POST code
func addProduce(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
var newProduceItem Produce
_ = json.NewDecoder(r.Body).Decode(&newProduceItem)
re := regexp.MustCompile("^[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}$")
if re.MatchString(newProduceItem.Code) == true && len(newProduceItem.Name) > 0 {
newProduceItem.Unit_Price = math.Round(newProduceItem.Unit_Price*100) / 100 //rounds to the nearest cent
produce = append(produce, newProduceItem)
json.NewEncoder(w).Encode(newProduceItem)
} else {
http.Error(w, fmt.Sprintf("Incorrect produce code sequence or product name. Example code sequence: A12T-4GH7-QPL9-3N4M"), http.StatusBadRequest)
}
}
It is called in the main() function as seen here.
func main() {
router := mux.NewRouter()
router.HandleFunc("/produce", addProduce).Methods("POST")
log.Fatal(http.ListenAndServe(":8000", router))
}
Here an example of JSON data that is working when I POST to it in Postman
{
"name":"Peach",
"code": "TTTT-44D4-A12T-1224",
"unit_price": 5.3334
}
I want to be able to post multiple produce items at once such as....
[
{
"name": "Green Pepper",
"code": "YRT6-72AS-K736-L4AR",
"unit_price": 0.79
},
{
"name": "Gala Apple",
"code": "TQ4C-VV6T-75ZX-1RMR",
"unit_price": 3.59
},
]
Thank you

Answer 1

There are clearly many ways to go about it, here is one
package main
import (
"encoding/json"
"fmt"
"log"
"math"
"net/http"
"regexp"
"github.com/gorilla/mux"
)
type Produce struct {
Name string `json:"name"`
Code string `json:"code"`
Unit_Price float64 `json:"unit_price"`
}
type ProduceList []Produce
// global var where all produce is kept,
// not persistent
var produce ProduceList
func addProduce(w http.ResponseWriter, r *http.Request) {
// we accept a json and decode it into a slice of structs
var newProduceItems ProduceList
err := json.NewDecoder(r.Body).Decode(&newProduceItems)
if err != nil {
log.Panic(err)
}
var tempItems ProduceList
re := regexp.MustCompile("^[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}-[a-zA-Z0-9]{4}$")
// iterate over each element in the posted json and validate
// when validated, add to the temporary accumulator
// if not validated, error out and stop
for idx, produceItem := range newProduceItems {
if !re.MatchString(produceItem.Code) || len(produceItem.Name) <= 0 {
errMsg := fmt.Sprintf("Item %d: Incorrect produce code sequence or product name. Example code sequence: A12T-4GH7-QPL9-3N4M", idx)
http.Error(w, errMsg, http.StatusBadRequest)
return
}
produceItem.Unit_Price = math.Round(produceItem.Unit_Price*100) / 100 //rounds to the nearest cent
tempItems = append(tempItems, produceItem)
}
// after validation, append new items to the global accumulator and respond back with added items
produce = append(produce, tempItems...)
w.Header().Set("Content-Type", "application/json")
if err = json.NewEncoder(w).Encode(newProduceItems); err != nil {
log.Panic(err)
}
}
func main() {
router := mux.NewRouter()
router.HandleFunc("/produce", addProduce).Methods("POST")
log.Fatal(http.ListenAndServe(":8000", router))
}